In Vitro Antioxidant and Cancer Inhibitory Activity of a Colored Avocado Seed Extract

Avocado (Persea americana) seeds have been used traditionally for a number of health-related indications. Because of its high polyphenol content, we investigated the potential antioxidant and anticancer effects of a colored avocado seed extract (CASE). CASE exhibited an oxygen radical acceptance capacity value of 2012 +/- 300 trolox equivalents/mg. CASE reduced lipid hydroperoxide formation in an oil-in-water emulsion (33% reduction at 500 mu g/mL). CASE dose-dependently reduced the viability of human breast (MCF7), lung (H1299), colon (HT29), and prostate (LNCaP) cancer cells in vitro. The half maximal inhibitory concentrations ranged from 19 to 132 mu g/mL after treatment for 48 h. CASE treatment downregulated the expression of cyclin D-1 and E-2 in LNCaP cells. This was associated with cell G(0)/G(1) phase cycle arrest. CASE also dose-dependently induced apoptosis in LNCaP cells. CASE reduced nuclear translocation of nuclear factor kappa B, a prosurvival signal. Further studies are needed to examine these effects in in vivo models.